CN102608208B - Dual-axis linkage based rapid scanning method of scanning acoustic microscope - Google Patents

Abstract

The invention discloses a dual-axis linkage based rapid scanning method of a scanning acoustic microscope. The method comprises the steps of: (1) setting a scanning area S=(N.a)*(N.a), and starting moving while taking Lscan=(N-1)a/ as the magnitude of motion displacements of motors at axes X and Y, wherein the motion directions of the axes X and Y are all positive directions; (2) when the two motors are stopped, changing the direction of the axis Y, maintaining the axis X unchanged, and moving while taking Lstep=a/ as the magnitudes of the motion displacements of the motors at the axes X and Y; (3) after the two motors are stopped, changing the motion direction of the axis X, maintaining the axis Y unchanged, and continuously starting the motion of the motors at the axes X and Y, wherein the magnitudes of displacements are both Lscan; (4) after the two motors are stopped, changing the motion direction of the axis X, maintaining the axis Y unchanged, and continuously starting the motion of the motors at the axes X and Y, wherein the magnitudes of the displacements are both Lstep; and (5) after the motors are stopped, repeating the steps from (1) to (4) until an entire image is scanned completely. According to the invention, on the premise of not changing motion system hardware conditions and not decreasing imaging resolution, the scanning efficiency can be increased by more than 20%.

Description

A kind of scanning ultrasonic microscope fast scanning method based on Dual-spindle linked

Technical field

The present invention relates to the method for micro-imaging rapid scanning, particularly a kind of scanning ultrasonic microscope fast scanning method based on Dual-spindle linked.

Background technology

Scanning ultrasonic microscope (SAM:Scanning Acoustic Microscope) is widely used in Non-Destructive Testing and the assessment of the Key Electron Device and precision mechanical part, is also widely used in the microscopic observation of biological tissue simultaneously.

In scanning ultrasonic microscope, often adopt two-dimentional machinery scanning mechanism to carry the detection of having popped one's head in to whole sample.The actuator of scanning mechanism generally all adopts linear electric motors or electric rotating machine to add precision ball screw.Traditional two-dimentional machinery scan pattern is grid scan pattern, makes X-axis motor be responsible for line scanning, the complete a line of every scanning, and once, step size is a corresponding size of pixel in y-axis motor stepping.When X-axis motor carries out line scanning, by the grating signal of X-axis motor, trigger high-speed AD card and gather echoed signal, and be treated in real time the gray-scale value at this some place in two dimensional image.What X-axis motor was reciprocal scans sample, until been scanned.

In order to improve the speed of scanning ultrasound wave micro-imaging, German KSI Inc. has adopted many probes sweeping scheme simultaneously, and each scanning probe one sub regions, then gets up each sub-region stitching, forms final scanning result.Adopt N probe, just can save so N sweep time doubly.But this method has obviously increased cost.At present, the mode that external major company raises the efficiency is all the hardware configuration of each motor to be proposed to optimize under existing grid scan pattern, meeting under the prerequisite of kinematic accuracy, improves as much as possible the speed of X or Y motor.But this mode can not essence must significantly improve motor speed, and the maximal value of motor speed is limited to grating frequency and resolution.

External to having proposed spiral scan pattern in the research of AFM, but this scan pattern has not only increased controller burden, and the picture point under polar coordinates is transformed under cartesian coordinate system and can brings corresponding site error again, image is processed comparatively loaded down with trivial details.In spiral scan, scan efficiency must be sacrificed the stability that guarantee is good to some extent, and compares with traditional raster mode its sweep time and do not have advantage in essence.Tradition grid scan pattern remains the microscopical conventional scan pattern of sonde-type of industry member mechanical scanning class at present.

But the scan pattern of traditional grid fails to make full use of the collaborative work of X-axis and y-axis motor, in scanning process, be that a driven by motor ultrasonic probe scans all the time, inefficiency.Based on this, a kind of quick grid scan pattern based on Dual-spindle linked formula is proposed, through theory, calculate and experimental results show that, in the situation that not changing any system hardware condition (as controller, driver etc.), can improve sweep speed more than 20%, and can not reduce the resolution of the rear imaging of scanning.

Summary of the invention

The object of the invention is, in order to improve the efficiency of the scanning imagery of scanning ultrasonic microscope, to propose a kind of scanning ultrasonic microscope fast scanning method based on Dual-spindle linked.

Scanning ultrasonic microscope fast scanning method based on Dual-spindle linked, adopt scanning ultrasonic microscope, scanning ultrasonic microscope comprises ultrasonic probe, X-axis motor, y-axis motor, Z axis motor, tank, electric machine controller, ultrasonic transmitter-receiver, computing machine, display, detected sample; Detected sample is placed in tank, ultrasonic probe be located at detected sample directly over, the top of ultrasonic probe is connected in Z axis motor, Z axis motor is connected with y-axis motor, y-axis motor is connected with X-axis motor, and X-axis motor, y-axis motor, Z axis motor are connected with electric machine controller, and ultrasonic probe is connected with ultrasonic transmitter-receiver, computing machine is connected with ultrasonic transmitter-receiver, electric machine controller, display respectively, and the step of method is as follows:

1) after the start of scanning ultrasonic microscope, place detected sample, ultrasonic probe transmitting ultrasound wave;

2) size of scan area S=(Na) * (Na) is set in the computing machine of scanning ultrasonic microscope, wherein N by the resolution of one-tenth image, the size that a is single pixel;

3) y-axis motor is moved along positive dirction, X-axis motor moves along negative direction, order for the size of X-axis motor and y-axis motor moving displacement, X-axis motor and y-axis motor be setting in motion simultaneously, and its resultant velocity makes ultrasonic probe in XY plane, complete a line scanning to detected sample;

4) after line scanning finishes, then changing y-axis motor direction of motion is negative direction, and X-axis motor movement direction is constant, and order

for the size of X-axis motor and y-axis motor moving displacement, X-axis motor and y-axis motor be setting in motion simultaneously, and its resultant velocity makes ultrasonic probe do micro-stepping;

5) after micro-stepping finishes, then to change X-axis motor movement direction be positive dirction, and y-axis motor direction of motion is negative direction not yet, order

for the size of X-axis motor and y-axis motor moving displacement, X-axis motor and y-axis motor be setting in motion simultaneously, and its resultant velocity makes ultrasonic probe in XY plane, complete the line scanning again to detected sample;

6) after line scanning finishes again, and then to change X-axis motor movement direction be negative direction, and y-axis motor direction of motion is constant, and order

for the size of the detected sample of X and y-axis motor moving displacement, the detected sample of X and y-axis motor be setting in motion simultaneously, and its resultant velocity makes ultrasonic probe do micro-stepping;

7) after micro-stepping finishes, repeating step 3) to step 6), detected sample is carried out to flyback retrace, until entire image been scanned.

The beneficial effect that the present invention compared with prior art has is:

1) the present invention can improve scanning ultrasonic microscope scanning imagery efficiency more than 20%;

2) the invention belongs to the change to motion control arithmetic in X and Y electric machine controller, can not bring the change to hardware system, in the time of also can not causing image mapped, do not produce site error, can not reduce the resolution after scanning imagery.

Accompanying drawing explanation

Fig. 1 is scanning ultrasonic microscope agent structure schematic diagram;

Fig. 2 is the motion control block diagram of motor on XY scanning platform in the present invention;

Fig. 3 is the track while scan schematic diagram of traditional grid scan pattern of the present invention;

Fig. 4 is the track while scan schematic diagram of the quick grid scan pattern based on Dual-spindle linked of the present invention;

Fig. 5 is that scanning ultrasonic microscope carries out the result contrast of scanning imagery under traditional grid scanning and quick grid scan pattern to same coin.

Embodiment

Scanning ultrasonic microscope fast scanning method based on Dual-spindle linked, adopt scanning ultrasonic microscope, scanning ultrasonic microscope comprises ultrasonic probe, X-axis motor, y-axis motor, Z axis motor, tank, electric machine controller, ultrasonic transmitter-receiver, computing machine, display, detected sample, detected sample is placed in tank, ultrasonic probe be located at detected sample directly over, the top of ultrasonic probe is connected in Z axis motor, Z axis motor is connected with y-axis motor, y-axis motor is connected with X-axis motor, X-axis motor, y-axis motor, Z axis motor is connected with electric machine controller, ultrasonic probe is connected with ultrasonic transmitter-receiver, computing machine respectively with ultrasonic transmitter-receiver, electric machine controller, display is connected, the ultrasonic echo signal of detected sample as calculated in machine signal after processing, can be converted into corresponding gray-scale map, if obtain the two dimensional image of whole detected sample, need to make ultrasonic probe complete the scanning to detected sample by the two-dimentional machinery motion of X-axis motor and y-axis motor, the step of method is as follows:

1) after the start of scanning ultrasonic microscope, place detected sample, ultrasonic probe transmitting ultrasound wave;

2) size of scan area S=(Na) * (Na) is set in the computing machine of scanning ultrasonic microscope, wherein N by the resolution of one-tenth image, the size that a is single pixel;

3) y-axis motor is moved along positive dirction, X-axis motor moves along negative direction, order

for the size of X-axis motor and y-axis motor moving displacement, X-axis motor and y-axis motor be setting in motion simultaneously, and its resultant velocity makes ultrasonic probe in XY plane, complete a line scanning to detected sample;

4) after line scanning finishes, then changing y-axis motor direction of motion is negative direction, and X-axis motor movement direction is constant, and order

for the size of X-axis motor and y-axis motor moving displacement, X-axis motor and y-axis motor be setting in motion simultaneously, and its resultant velocity makes ultrasonic probe do micro-stepping;

5) after micro-stepping finishes, then to change X-axis motor movement direction be positive dirction, and y-axis motor direction of motion is negative direction not yet, order

for the size of X-axis motor and y-axis motor moving displacement, X-axis motor and y-axis motor be setting in motion simultaneously, and its resultant velocity makes ultrasonic probe in XY plane, complete the line scanning again to detected sample;

6) after line scanning finishes again, and then to change X-axis motor movement direction be negative direction, and y-axis motor direction of motion is constant, and order

for the size of the detected sample of X and y-axis motor moving displacement, the detected sample of X and y-axis motor be setting in motion simultaneously, and its resultant velocity makes ultrasonic probe do micro-stepping;

7) after micro-stepping finishes, repeating step 3) to step 6), detected sample is carried out to flyback retrace, until entire image been scanned.

For the region of scan area S=(Na) * (Na), the scan efficiency of the fast scanning method below traditional grid scan method and the present invention being proposed is made comparison.

1) traditional grid scan method:

As shown in Figure 3, X-axis motor is responsible for line scanning to the track while scan of tradition grid scan method, and y-axis motor is responsible for stepping.The theoretical calculation expression of the T.T. of scanning is:

T ₁＝N·t _{scan_1}+(N-1)·t _{step_1} (1)

, t wherein _{scan_1}and t _{step_1}be respectively a line scanning and stepping time used once.Suppose to adopt T-shape velocity diagram to carry out interpolation, a in X and y-axis motor controller _mand v _mbe respectively acceleration and maximal rate that X and y-axis motor kinematic system allow.While generally carrying out large area imaging, have

be in line scanning, to have the uniform motion stage, but differ when resolution is very high, guarantee surely

guarantee to exist in stepping process the at the uniform velocity stage.So:

$t_{\mathrm{scan}\_1}=\frac{v_m}{a_m}+\frac{(N-1)a}{v_m}---\left(2\right)$

$t_{\mathrm{step}\_1}=\left\{\begin{array}{cc}\frac{a}{v_m}+\frac{v_m}{a_m},& a\&GreaterEqual;\frac{v_m^2}{a_m}\\ 2\sqrt{\frac{a}{a_m}},& a<\frac{v_m^2}{a_m}\end{array}\right.,---\left(3\right)$

To in equation (2) and (3) substitution (1), obtain:

$T_1=\left\{\begin{array}{cc}\frac{(N^2-1)a}{v_m}+\frac{(2N-1)v_m}{a_m},& a\&GreaterEqual;\frac{v_m^2}{a_m}\\ \frac{N(N-1)a}{v_m}+\frac{{\mathrm{Nv}}_m}{a_m}+2(N-1)\sqrt{\frac{a}{a_m}},& a<\frac{v_m^2}{a_m}\end{array}\right..---\left(4\right)$

When N > > 1, have:

$T_1=\frac{(N^2-1)a}{v_m}---\left(5\right)$

2) fast scanning method that the present invention proposes:

As shown in Figure 4, X-axis and y-axis motor are responsible for line scanning and stepping to the track while scan of the fast scanning method that the present invention proposes simultaneously, and the theoretical calculation expression of the T.T. of scanning is:

T ₂＝N·t _{scan_2}+(N-1)·t _{step_2} (6)

, t wherein _{scan_2}and t _{step_2}be respectively a line scanning and stepping time used once.Suppose to adopt T-shape velocity diagram to carry out interpolation, a in X and y-axis motor controller _mand v _mbe respectively acceleration and maximal rate that X and y-axis motor kinematic system allow.While generally carrying out large area imaging, have

be to have the uniform motion stage during X and y-axis motor scan, but differ when resolution is very high, guarantee surely

guarantee to exist in stepping process the at the uniform velocity stage.So:

$t_{\mathrm{scam}\_2}=\frac{v_m}{a_m}+\frac{(N-1)a}{\sqrt{2}{v}_m}---\left(7\right)$

$t_{\mathrm{step}\_2}=\left\{\begin{array}{cc}\frac{a}{\sqrt{2}{v}_m}+\frac{v_m}{a_m},& a\&GreaterEqual;\frac{v_m^2}{a_m}\\ \sqrt{\frac{2\sqrt{2}a}{a_m}},& a<\frac{v_m^2}{a_m}\end{array}\right.,---\left(8\right)$

To in equation (2) and (3) substitution (1), obtain:

$T_2=\left\{\begin{array}{cc}\frac{(N^2-1)a}{\sqrt{2}{v}_m}+\frac{(2N-1)v_m}{a_m},& a\&GreaterEqual;\frac{v_m^2}{a_m}\\ \frac{N(N-1)a}{\sqrt{2}{v}_m}+\frac{{\mathrm{Nv}}_m}{a_m}+(N-1)\sqrt{\frac{2\sqrt{2}a}{a_m}},& a<\frac{v_m^2}{a_m}\end{array}\right..---\left(9\right)$

When N > > 1, have:

$T_2=\frac{(N^2-1)a}{\sqrt{2}{v}_m}---\left(10\right)$

Now,

be that the fast scanning method that the present invention proposes is compared with traditional grid scan method, can improve sweep speed 29%, scan efficiency is significantly improved.

Below in conjunction with embodiment and accompanying drawing, the present invention is done further and described in detail.

Using monobasic Renminbi coin as sweep object, and scan area S is 20 * 20mm ², in the situation that image resolution ratio is 512 * 512, N=512, a=39.06 μ m.The fast scanning method that uses traditional grid scan method and the present invention to propose carries out scanning imagery to above-mentioned zone.

The execution step of tradition grid scan method is as follows:

1), after scanning ultrasonic microscope start, by controlling software, determine motor advance step-length a=39.0625 μ m and scanning area 20 * 20mm ²(N=512);

2) ultrasonic probe is moved to the top of monobasic coin, use self-focusing control system to control ultrasonic probe and measured material relative position;

3) according to the track while scan setting in motion shown in Fig. 3, make X-axis motor along the positive dirction 19.96mm that moves, X-axis motor stops rear y-axis motor along negative direction stepping 39.06 μ m;

4) make X-axis motor along the negative direction 19.96mm that moves, X-axis motor stops rear y-axis motor again along negative direction stepping 39.06 μ m again;

5) repeat 3) to 4) in step, until complete the whole scanning that is scanned region of coin;

6) when X-axis motor carries out line scanning each time, grating signal triggering high-speed AD card by X-axis motor carrys out acquisition pulse formula ultrasonic echo signal, computing machine will be processed and feature extraction echoed signal, and be converted into the gradation of image value at this some place, the image obtaining is as shown in Fig. 5 (a), and be 544s whole sweep time.

The execution step of the fast scanning method that the present invention proposes is as follows:

1) after the start of scanning ultrasonic microscope, place monobasic coin, ultrasonic probe is moved to the top of monobasic coin, ultrasonic probe transmitting ultrasound wave, is used self-focusing control system to control ultrasonic probe and coin relative position;

2) in scanning ultrasonic microscope software, scan area S=(Na) * (Na)=20 * 20mm is set ², wherein N=512 by the resolution of one-tenth image, the size that a=39.06 μ m is single pixel.

3) the motion control block diagram of X-axis motor and y-axis motor as shown in Figure 2, the control mode that adopts feed-forward loop to combine with PID position feedback, speed feedback, to improve the track following performance of scan module, according to the track while scan setting in motion shown in Fig. 4, y-axis motor is moved along positive dirction, X-axis motor moves along negative direction, order

for the size of X and y-axis motor moving displacement, X-axis motor and y-axis motor be setting in motion simultaneously, and the resultant motion of X-axis motor and y-axis motor completes to coin line scanning ultrasonic probe in XY plane;

4) then changing y-axis motor direction of motion is negative direction, and X-axis motor movement direction is constant, and order

for the size of X-axis motor and y-axis motor moving displacement, X-axis motor and y-axis motor be setting in motion simultaneously, and the resultant motion of X-axis motor and y-axis motor makes probe do micro-stepping;

5) changing X-axis motor movement direction is positive dirction again, and y-axis motor direction of motion is negative direction not yet, makes L _scan=14.12mm is the size of X-axis motor and y-axis motor moving displacement, and X-axis motor and y-axis motor be setting in motion simultaneously, and the resultant motion of X-axis motor and y-axis motor makes the line scanning again of probe complete paired samples in XY plane;

6) and then to change X-axis motor movement direction be negative direction, y-axis motor direction of motion is constant, and order

for the size of X-axis motor and y-axis motor moving displacement, X-axis motor and y-axis motor be setting in motion simultaneously, and the resultant motion of X-axis motor and y-axis motor makes probe do micro-stepping;

7) repeat 3) to 6) in step, flyback retrace is carried out in the detected region of coin, until entire image been scanned.The image obtaining is as shown in Fig. 5 (b), and be 402s whole sweep time, compares with traditional grid scan method, improves sweep speed 26.1%.

The fast scanning method that the present invention proposes as can be seen from Figure 5 can't affect to some extent on the quality of image, but because the resultant velocity that has utilized X-axis motor and y-axis motor simultaneously to move, fast scanning method proposed by the invention can be realized scanning faster.

Claims (1)

1. the scanning ultrasonic microscope fast scanning method based on Dual-spindle linked, adopt scanning ultrasonic microscope, scanning ultrasonic microscope comprises ultrasonic probe, X-axis motor, y-axis motor, Z axis motor, tank, electric machine controller, ultrasonic transmitter-receiver, computing machine, display, detected sample; Detected sample is placed in tank, ultrasonic probe be located at detected sample directly over, the top of ultrasonic probe is connected in Z axis motor, Z axis motor is connected with y-axis motor, y-axis motor is connected with X-axis motor, and X-axis motor, y-axis motor, Z axis motor are connected with electric machine controller, and ultrasonic probe is connected with ultrasonic transmitter-receiver, computing machine is connected with ultrasonic transmitter-receiver, electric machine controller, display respectively, it is characterized in that the step of method is as follows:

1) after the start of scanning ultrasonic microscope, place detected sample, ultrasonic probe transmitting ultrasound wave;

2) in the computing machine of scanning ultrasonic microscope, scan area is set s=( na) * ( na) size, wherein nby the resolution of one-tenth image, asize for single pixel;

3) y-axis motor is moved along positive dirction, X-axis motor moves along negative direction, order l _scan =( n-1) a/

for the size of X-axis motor and y-axis motor moving displacement, X-axis motor and y-axis motor be setting in motion simultaneously, and its resultant velocity makes ultrasonic probe in XY plane, complete a line scanning to detected sample;

4) after line scanning finishes, then changing y-axis motor direction of motion is negative direction, and X-axis motor movement direction is constant, and order l _step = a/

for the size of X-axis motor and y-axis motor moving displacement, X-axis motor and y-axis motor be setting in motion simultaneously, and its resultant velocity makes ultrasonic probe do micro-stepping;

5) after micro-stepping finishes, then to change X-axis motor movement direction be positive dirction, and y-axis motor direction of motion is negative direction not yet, order l _scan =( n-1) a/

for the size of X-axis motor and y-axis motor moving displacement, X-axis motor and y-axis motor be setting in motion simultaneously, and its resultant velocity makes ultrasonic probe in XY plane, complete the line scanning again to detected sample;

6) after line scanning finishes again, and then to change X-axis motor movement direction be negative direction, and y-axis motor direction of motion is constant, and order l _step = a/ for the size of X-axis motor and y-axis motor moving displacement, X-axis motor and y-axis motor be setting in motion simultaneously, and its resultant velocity makes ultrasonic probe do micro-stepping;

7) after micro-stepping finishes, repeating step 3) to step 6), detected sample is carried out to flyback retrace, until entire image been scanned.

Images